Publicity and the Rule of Law

By the ‘Rule of Law’ I mean a set of formal and institutional features the law may possess in varying degrees. These features define an ideal, which laws have traditionally been expected to live up to. One of these features is publicity. Part of what constitutes the Rule of Law is the requirement that the laws should be public. This is the subject of this paper. When it is claimed that the Rule of Law requires that the laws should be public, what is to be understood by this claim? My main claim is that the Rule of Law requirement of publicity is best understood in terms of the notion of common, or mutual, knowledge. When it is required that the laws should be public, what should be meant by this is not only that each one of the law’s addressees should know what the law is, but also that everybody should know that everybody knows what the law is, that everybody should know that everybody knows that everybody knows what the law is, and so on. This may look unnecessarily complicated. I’ll try to show that this is a false impression, and that understanding the publicity requirement along these lines illuminates various aspects of the normative ideal the publicity requirement may be taken to embody.